Nonwoven composite containing an apertured elastic film

ABSTRACT

An elastic nonwoven composite that contains an elastic film laminated to one or more nonwoven web materials is provided. The composite is formed by passing the film through a nip to bond the film to the nonwoven web material(s). Concurrent with bond formation, apertures are also formed in the elastic film. The apertures are of a size sufficient to provide a desired level of texture, softness, hand feel, and/or aesthetic appeal to the composite without having a significant adverse effect on its elastic properties. Aperture and bond formation are accomplished in the present invention by selectively controlling certain parameters of the lamination process, such as film content, bonding pattern, degree of film tension, bonding conditions, etc.

BACKGROUND OF THE INVENTION

Elastic composites are commonly incorporated into products (e.g.,diapers, training pants, garments, etc.) to improve their ability tobetter fit the contours of the body. For example, the elastic compositemay be formed from an elastic film and one or more nonwoven webmaterials. The nonwoven web material may be joined to the elastic filmwhile the film is in a stretched condition so that the nonwoven webmaterial can gather between the locations where it is bonded to the filmwhen it is relaxed. The resulting elastic composite is stretchable tothe extent that the nonwoven web material gathered between the bondlocations allows the elastic film to elongate. Unfortunately, elasticfilms often have unpleasant tactile aesthetic properties, such asfeeling rubbery or tacky to the touch, making them unpleasant anduncomfortable against the wearer's skin. In an effort to improve theseproperties, attempts have been made to aperture the composite. Forexample, U.S. Pat. No. 6,830,800 to Curro, et al. describes a method inwhich an elastic material is joined between two webs. The elasticmaterial is apertured in regions coincident the bond sites so that thefirst and second webs are joined through the apertures. Despite thebenefits achieved, however, a need for improvement nevertheless remains.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the present invention, a method offorming a nonwoven composite is disclosed. The method comprises formingan elastic film from a polymer composition and passing the film and anonwoven web material through a nip formed by at least one patternedroll. At the nip, the film and the nonwoven web material are melt fusedand the film is concurrently formed with apertures without substantiallysoftening the polymer of the nonwoven web material. At least one of theapertures has a length of from about 200 to about 5000 micrometers.Further, the film is under tension at a stretch ratio of about 1.5 ormore in the machine direction at the nip.

In accordance with another embodiment of the present invention, anonwoven composite is disclosed that comprises an elastic filmpositioned adjacent and melt fused to a nonwoven web material at aplurality of discrete bond sites. The elastic film defines a pluralityof apertures having a perimeter about which the discrete bond sites areproximately located. At least one of the apertures has a length of fromabout 200 to about 5000 micrometers.

Other features and aspects of the present invention are described inmore detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth more particularly in the remainder of the specification, whichmakes reference to the appended figures in which:

FIG. 1 schematically illustrates a method for forming a compositeaccording to one embodiment of the present invention;

FIG. 2 illustrates one embodiment of an “S-weave” bonding pattern thatmay be used in accordance with the present invention;

FIG. 3 illustrates one embodiment of a “rib-knit” bonding pattern thatmay be used in accordance with the present invention;

FIG. 4 illustrates one embodiment of a “wire-weave” bonding pattern thatmay be used in accordance with the present invention;

FIG. 5 is a perspective view of grooved rolls that may be used in oneembodiment of the present invention; and

FIG. 6 is a cross-sectional view showing the engagement between two ofthe grooved rolls of FIG. 5;

FIG. 7 is cross-sectional view of one embodiment of the nonwovencomposite of the present invention;

FIG. 8 is a perspective view of a personal care product that may beformed in accordance with one embodiment of the present invention;

FIG. 9 is an SEM microphotograph (5 kv, 60×) of the sample formed inExample 1, showing apertures in the elastic film formed by the bars of arib-knit bonding pattern;

FIG. 10 is an SEM microphotograph (5 kv, 100×) of the sample formed inExample 1, showing apertures in the elastic film formed by the pins of arib-knit bonding pattern;

FIG. 11 is an SEM microphotograph (5 kv, 20×) of the sample formed inExample 1, showing apertures in the elastic film formed by a rib-knitbonding pattern;

FIG. 12 is an SEM microphotograph (5 kv, 250×) of the sample formed inExample 1;

FIG. 13 is an SEM microphotograph (5 kv, 120×) of the sample formed inExample 1;

FIG. 14 is an SEM microphotograph (5 kv, 30×) of the sample formed inExample 1;

FIG. 15 is an SEM microphotograph (5 kv, 30×) of the sample formed inExample 1;

FIG. 16 is an SEM microphotograph (5 kv, 50×) of the sample formed inExample 1; and

FIG. 17 is an SEM microphotograph (5 kv, 30×) of the sample formed inExample 1.

Repeat use of reference characters in the present specification anddrawings is intended to represent same or analogous features or elementsof the invention.

DETAILED DESCRIPTION OF REPRESENTATIVE EMBODIMENTS Definitions

As used herein the term “nonwoven web” generally refers to a web havinga structure of individual fibers or threads which are interlaid, but notin an identifiable manner as in a knitted fabric. Examples of suitablenonwoven fabrics or webs include, but are not limited to, meltblownwebs, spunbond webs, bonded carded webs, airlaid webs, coform webs,hydraulically entangled webs, and so forth.

As used herein, the term “meltblown web” generally refers to a nonwovenweb that is formed by a process in which a molten thermoplastic materialis extruded through a plurality of fine, usually circular, diecapillaries as molten fibers into converging high velocity gas (e.g.air) streams that attenuate the fibers of molten thermoplastic materialto reduce their diameter, which may be to microfiber diameter.Thereafter, the meltblown fibers are carried by the high velocity gasstream and are deposited on a collecting surface to form a web ofrandomly dispersed meltblown fibers. Such a process is disclosed, forexample, in U.S. Pat. No. 3,849,241 to Butin, et al., which isincorporated herein in its entirety by reference thereto for allpurposes. Generally speaking, meltblown fibers may be microfibers thatare substantially continuous or discontinuous, generally smaller than 10microns in diameter, and generally tacky when deposited onto acollecting surface.

As used herein, the term “spunbond web” generally refers to a webcontaining small diameter substantially continuous fibers. The fibersare formed by extruding a molten thermoplastic material from a pluralityof fine, usually circular, capillaries of a spinnerette with thediameter of the extruded fibers then being rapidly reduced as by, forexample, eductive drawing and/or other well-known spunbondingmechanisms. The production of spunbond webs is described andillustrated, for example, in U.S. Pat. Nos. 4,340,563 to Appel, et al.,3,692,618 to Dorschner, et al., 3,802,817 to Matsuki, et al., 3,338,992to Kinney, 3,341,394 to Kinney, 3,502,763 to Hartman, 3,502,538 to Levv,3,542,615 to Dobo, et al., and 5,382,400 to Pike, et al., which areincorporated herein in their entirety by reference thereto for allpurposes. Spunbond fibers are generally not tacky when they aredeposited onto a collecting surface. Spunbond fibers may sometimes havediameters less than about 40 microns, and are often between about 5 toabout 20 microns.

As used herein, the terms “machine direction” or “MD” generally refersto the direction in which a material is produced. The term“cross-machine direction” or “CD” refers to the direction perpendicularto the machine direction.

As used herein the terms “extensible” or “extensibility” generallyrefers to a material that stretches or extends in the direction of anapplied force by at least about 25%, in some embodiments about 50%, andin some embodiments, at least about 75% of its relaxed length or width.An extensible material does not necessarily have recovery properties.For example, an elastomeric material is an extensible material havingrecovery properties. A meltblown web may be extensible, but not haverecovery properties, and thus, be an extensible, non-elastic material.

As used herein, the term “elastomeric” and “elastic” and refers to amaterial that, upon application of a stretching force, is stretchable inat least one direction (such as the CD direction), and which uponrelease of the stretching force, contracts/returns to approximately itsoriginal dimension. For example, a stretched material may have astretched length that is at least 50% greater than its relaxedunstretched length, and which will recover to within at least 50% of itsstretched length upon release of the stretching force. A hypotheticalexample would be a one (1) inch sample of a material that is stretchableto at least 1.50 inches and which, upon release of the stretching force,will recover to a length of not more than 1.25 inches. Desirably, thematerial contracts or recovers at least 50%, and even more desirably, atleast 80% of the stretched length.

As used herein, the terms “necked” and “necked material” generally referto any material that has been drawn in at least one dimension (e.g.,machine direction) to reduce its transverse dimension (e.g.,cross-machine direction) so that when the drawing force is removed, thematerial may be pulled back to its original width. The necked materialgenerally has a higher basis weight per unit area than the un-neckedmaterial. When the necked material is pulled back to its original width,it should have about the same basis weight as the un-necked material.This differs from the orientation of a film in which the film is thinnedand the basis weight is reduced. The necking method typically involvesunwinding a material from a supply roll and passing it through a brakenip roll assembly driven at a given linear speed. A take-up roll or nip,operating at a linear speed higher than the brake nip roll, draws thematerial and generates the tension needed to elongate and neck thematerial.

As used herein, the term “thermal point bonding” generally refers to aprocess performed, for example, by passing a material between apatterned roll (e.g., calender roll) and another roll (e.g., anvilroll), which may or may not be patterned. One or both of the rolls aretypically heated.

As used herein, the term “ultrasonic bonding” generally refers to aprocess performed, for example, by passing a material between a sonichorn and a patterned roll (e.g., anvil roll). For instance, ultrasonicbonding through the use of a stationary horn and a rotating patternedanvil roll is described in U.S. Pat. Nos. 3,939,033 to Grgach. et al.,3,844,869 to Rust Jr., and 4,259,399 to Hill, which are incorporatedherein in their entirety by reference thereto for all purposes.Moreover, ultrasonic bonding through the use of a rotary horn with arotating patterned anvil roll is described in U.S. Pat. Nos. 5,096,532to Neuwirth, et al., 5,110,403 to Ehlert, and 5,817,199 to Brennecke, etal., which are incorporated herein in their entirety by referencethereto for all purposes. Of course, any other ultrasonic bondingtechnique may also be used in the present invention.

DETAILED DESCRIPTION

Reference now will be made in detail to various embodiments of theinvention, one or more examples of which are set forth below. Eachexample is provided by way of explanation, not limitation of theinvention. In fact, it will be apparent to those skilled in the art thatvarious modifications and variations may be made in the presentinvention without departing from the scope or spirit of the invention.For instance, features illustrated or described as part of oneembodiment, may be used on another embodiment to yield a still furtherembodiment. Thus, it is intended that the present invention cover suchmodifications and variations.

Generally speaking, the present invention is directed to a nonwovencomposite that contains an elastic film laminated to one or morenonwoven web materials. The composite is formed by passing the filmthrough a nip to bond the film to the nonwoven web material(s).Concurrent with bond formation, apertures are also formed in the elasticfilm. The apertures are of a size sufficient to provide a desired levelof texture, softness, hand feel, and/or aesthetic appeal to thecomposite without having a significant adverse effect on its elasticproperties. Aperture and bond formation are accomplished in the presentinvention by selectively controlling certain parameters of thelamination process, such as film content, bonding pattern, degree offilm tension, bonding conditions, etc. In this regard, variousembodiments of the present invention will now be described in moredetail.

I. Elastic Film

The elastic film of the present invention is formed from one or moreelastomeric polymers that are melt-processable, i.e. thermoplastic. Anyof a variety of thermoplastic elastomeric polymers may generally beemployed in the present invention, such as elastomeric polyesters,elastomeric polyurethanes, elastomeric polyamides, elastomericcopolymers, elastomeric polyolefins, and so forth. In one particularembodiment, elastomeric semi-crystalline polyolefins are employed due totheir unique combination of mechanical and elastomeric properties. Thatis, the mechanical properties of such semi-crystalline polyolefinsallows for the formation of films that readily aperture during thermalbonding, but yet retain their elasticity.

Semi-crystalline polyolefins have or are capable of exhibiting asubstantially regular structure. For example, semi-crystallinepolyolefins may be substantially amorphous in their undeformed state,but form crystalline domains upon stretching. The degree ofcrystallinity of the olefin polymer may be from about 3% to about 30%,in some embodiments from about 5% to about 25%, and in some embodiments,from about 5% and about 15%. Likewise, the semi-crystalline polyolefinmay have a latent heat of fusion (ΔH_(f)), which is another indicator ofthe degree of crystallinity, of from about 15 to about 75 Joules pergram (“J/g”), in some embodiments from about 20 to about 65 J/g, and insome embodiments, from 25 to about 50 J/g. The semi-crystallinepolyolefin may also have a Vicat softening temperature of from about 10°C. to about 100° C., in some embodiments from about 20° C. to about 80°C., and in some embodiments, from about 30° C. to about 60° C. Thesemi-crystalline polyolefin may have a melting temperature of from about20° C. to about 120° C., in some embodiments from about 35° C. to about90° C., and in some embodiments, from about 40° C. to about 80° C. Thelatent heat of fusion (ΔH_(f)) and melting temperature may be determinedusing differential scanning calorimetry (“DSC”) in accordance with ASTMD-3417 as is well known to those skilled in the art. The Vicat softeningtemperature may be determined in accordance with ASTM D-1525.

Exemplary semi-crystalline polyolefins include polyethylene,polypropylene, blends and copolymers thereof. In one particularembodiment, a polyethylene is employed that is a copolymer of ethyleneand an α-olefin, such as a C₃-C₂₀ α-olefin or C₃-C₁₂ α-olefin. Suitableα-olefins may be linear or branched (e.g., one or more C₁-C₃ alkylbranches, or an aryl group). Specific examples include 1-butene;3-methyl-1-butene; 3,3-dimethyl-1-butene; 1-pentene; 1-pentene with oneor more methyl, ethyl or propyl substituents; 1-hexene with one or moremethyl, ethyl or propyl substituents; 1-heptene with one or more methyl,ethyl or propyl substituents; 1-octene with one or more methyl, ethyl orpropyl substituents; 1-nonene with one or more methyl, ethyl or propylsubstituents; ethyl, methyl or dimethyl-substituted 1-decene;1-dodecene; and styrene. Particularly desired α-olefin comonomers are1-butene, 1-hexene and 1-octene. The ethylene content of such copolymersmay be from about 60 mole % to about 99 mole %, in some embodiments fromabout 80 mole % to about 98.5 mole %, and in some embodiments, fromabout 87 mole % to about 97.5 mole %. The α-olefin content may likewiserange from about 1 mole % to about 40 mole %, in some embodiments fromabout 1.5 mole % to about 15 mole %, and in some embodiments, from about2.5 mole % to about 13 mole %.

The density of the polyethylene may vary depending on the type ofpolymer employed, but generally ranges from 0.85 to 0.96 grams per cubiccentimeter (“g/cm³”). Polyethylene “plastomers”, for instance, may havea density in the range of from 0.85 to 0.91 g/cm³. Likewise, “linear lowdensity polyethylene” (“LLDPE”) may have a density in the range of from0.91 to 0.940 g/cm³; “low density polyethylene” (“LDPE”) may have adensity in the range of from 0.910 to 0.940 g/cm³; and “high densitypolyethylene” (“HDPE”) may have density in the range of from 0.940 to0.960 g/cm³. Densities may be measured in accordance with ASTM 1505.

Particularly suitable polyethylene copolymers are those that are“linear” or “substantially linear.” The term “substantially linear”means that, in addition to the short chain branches attributable tocomonomer incorporation, the ethylene polymer also contains long chainbranches in that the polymer backbone. “Long chain branching” refers toa chain length of at least 6 carbons. Each long chain branch may havethe same comonomer distribution as the polymer backbone and be as longas the polymer backbone to which it is attached. Preferred substantiallylinear polymers are substituted with from 0.01 long chain branch per1000 carbons to 1 long chain branch per 1000 carbons, and in someembodiments, from 0.05 long chain branch per 1000 carbons to 1 longchain branch per 1000 carbons. In contrast to the term “substantiallylinear”, the term “linear” means that the polymer lacks measurable ordemonstrable long chain branches. That is, the polymer is substitutedwith an average of less than 0.01 long chain branch per 1000 carbons.

The density of a linear ethylene/α-olefin copolymer is a function ofboth the length and amount of the α-olefin. That is, the greater thelength of the α-olefin and the greater the amount of α-olefin present,the lower the density of the copolymer. Although not necessarilyrequired, linear polyethylene “plastomers” are particularly desirable inthat the content of α-olefin short chain branching content is such thatthe ethylene copolymer exhibits both plastic and elastomericcharacteristics—i.e., a “plastomer.” Because polymerization withα-olefin comonomers decreases crystallinity and density, the resultingplastomer normally has a density lower than that of polyethylenethermoplastic polymers (e.g., LLDPE), but approaching and/or overlappingthat of an elastomer. For example, the density of the polyethyleneplastomer may be 0.91 grams per cubic centimeter (g/cm³) or less, insome embodiments, from 0.85 to 0.88 g/cm³, and in some embodiments, from0.85 g/cm³ to 0.87 g/cm³. Despite having a density similar toelastomers, plastomers generally exhibit a higher degree ofcrystallinity, are relatively non-tacky, and may be formed into pelletsthat are non-adhesive and relatively free flowing.

The distribution of the α-olefin comonomer within a polyethyleneplastomer is typically random and uniform among the differing molecularweight fractions forming the ethylene copolymer. This uniformity ofcomonomer distribution within the plastomer may be expressed as acomonomer distribution breadth index value (“CDBI”) of 60 or more, insome embodiments 80 or more, and in some embodiments, 90 or more.Further, the polyethylene plastomer may be characterized by a DSCmelting point curve that exhibits the occurrence of a single meltingpoint peak occurring in the region of 50 to 110° C. (second meltrundown).

Preferred plastomers for use in the present invention are ethylene-basedcopolymer plastomers available under the designation EXACT™ fromExxonMobil Chemical Company of Houston, Tex. Other suitable polyethyleneplastomers are available under the designation ENGAGE™ and AFFINITY™from Dow Chemical Company of Midland, Mich. Still other suitableethylene polymers are available from The Dow Chemical Company under thedesignations DOWLEX™ (LLDPE) and ATTANE™ (ULDPE). Other suitableethylene polymers are described in U.S. Pat. Nos. 4,937,299 to Ewen etal.; 5,218,071 to Tsutsui et al.; 5,272,236 to Lai. et al.; and5,278,272 to Lai, et al., which are incorporated herein in theirentirety by reference thereto for all purposes.

Of course, the present invention is by no means limited to the use ofethylene polymers. For instance, propylene polymers may also be suitablefor use as a semi-crystalline polyolefin. Suitable plastomeric propylenepolymers may include, for instance, copolymers or terpolymers ofpropylene include copolymers of propylene with an α-olefin (e.g.,C₃-C₂₀), such as ethylene, 1-butene, 2-butene, the various penteneisomers, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-unidecene,1-dodecene, 4-methyl-1-pentene, 4-methyl-1-hexene, 5-methyl-1-hexene,vinylcyclohexene, styrene, etc. The comonomer content of the propylenepolymer may be about 35 wt. % or less, in some embodiments from about 1wt. % to about 20 wt. %, and in some embodiments, from about 2 wt. % toabout 10 wt. %. Preferably, the density of the polypropylene (e.g.,propylene/α-olefin copolymer) may be 0.91 grams per cubic centimeter(g/cm³) or less, in some embodiments, from 0.85 to 0.88 g/cm³, and insome embodiments, from 0.85 g/cm³ to 0.87 g/cm³. Suitable propylenepolymers are commercially available under the designations VISTAMAXX™from ExxonMobil Chemical Co. of Houston, Tex.; FINA™ (e.g., 8573) fromAtofina Chemicals of Feluy, Belgium; TAFMER™ available from MitsuiPetrochemical Industries; and VERSIFY™ available from Dow Chemical Co.of Midland, Mich. Other examples of suitable propylene polymers aredescribed in U.S. Pat. No. 6,500,563 to Datta. et al.; U.S. Pat. No.5,539,056 to Yang, et al.; and U.S. Pat. No. 5,596,052 to Resconi, etal., which are incorporated herein in their entirety by referencethereto for all purposes.

Any of a variety of known techniques may generally be employed to formthe semi-crystalline polyolefins. For instance, olefin polymers may beformed using a free radical or a coordination catalyst (e.g.,Ziegler-Natta). Preferably, the olefin polymer is formed from asingle-site coordination catalyst, such as a metallocene catalyst. Sucha catalyst system produces ethylene copolymers in which the comonomer israndomly distributed within a molecular chain and uniformly distributedacross the different molecular weight fractions. Metallocene-catalyzedpolyolefins are described, for instance, in U.S. Pat. Nos. 5,571,619 toMcAlpin et al.; 5,322,728 to Davis et al.; 5,472,775 to Obijeski et al.;5,272,236 to Lai et al.; and 6,090,325 to Wheat, et al., which areincorporated herein in their entirety by reference thereto for allpurposes. Examples of metallocene catalysts includebis(n-butylcyclopentadienyl)titanium dichloride,bis(n-butylcyclopentadienyl)zirconium dichloride,bis(cyclopentadienyl)scandium chloride, bis(indenyl)zirconiumdichloride, bis(methylcyclopentadienyl)titanium dichloride,bis(methylcyclopentadienyl)zirconium dichloride, cobaltocene,cyclopentadienyltitanium trichloride, ferrocene, hafnocene dichloride,isopropyl(cyclopentadienyl-1-flourenyl)zirconium dichloride, molybdocenedichloride, nickelocene, niobocene dichloride, ruthenocene, titanocenedichloride, zirconocene chloride hydride, zirconocene dichloride, and soforth. Polymers made using metallocene catalysts typically have a narrowmolecular weight range. For instance, metallocene-catalyzed polymers mayhave polydispersity numbers (M_(w)/M_(n)) of below 4, controlled shortchain branching distribution, and controlled isotacticity.

The melt flow index (MI) of the semi-crystalline polyolefins maygenerally vary, but is typically in the range of about 0.1 grams per 10minutes to about 100 grams per 10 minutes, in some embodiments fromabout 0.5 grams per 10 minutes to about 30 grams per 10 minutes, and insome embodiments, about 1 to about 10 grams per 10 minutes, determinedat 190° C. The melt flow index is the weight of the polymer (in grams)that may be forced through an extrusion rheometer orifice (0.0825-inchdiameter) when/subjected to a force of 5000 grams in 10 minutes at 190°C., and may be determined in accordance with ASTM Test Method D1238-E.

Of course, other thermoplastic polymers may also be used to form theelastic film, either alone or in conjunction with the semi-crystallinepolyolefins. For instance, a substantially amorphous block copolymer maybe employed that has at least two blocks of a monoalkenyl arene polymerseparated by at least one block of a saturated conjugated diene polymer.The monoalkenyl arene blocks may include styrene and its analogues andhomologues, such as o-methyl styrene; p-methyl styrene; p-tert-butylstyrene; 1,3 dimethyl styrene p-methyl styrene; etc., as well as othermonoalkenyl polycyclic aromatic compounds, such as vinyl naphthalene;vinyl anthrycene; and so forth. Preferred monoalkenyl arenes are styreneand p-methyl styrene. The conjugated diene blocks may includehomopolymers of conjugated diene monomers, copolymers of two or moreconjugated dienes, and copolymers of one or more of the dienes withanother monomer in which the blocks are predominantly conjugated dieneunits. Preferably, the conjugated dienes contain from 4 to 8 carbonatoms, such as 1,3 butadiene (butadiene); 2-methyl-1,3 butadiene;isoprene; 2,3 dimethyl-1,3 butadiene; 1,3 pentadiene (piperylene); 1,3hexadiene; and so forth.

The amount of monoalkenyl arene (e.g., polystyrene) blocks may vary, buttypically constitute from about 8 wt. % to about 55 wt. %, in someembodiments from about 10 wt. % to about 35 wt. %, and in someembodiments, from about 25 wt. % to about 35 wt. % of the copolymer.Suitable block copolymers may contain monoalkenyl arene endblocks havinga number average molecular weight from about 5,000 to about 35,000 andsaturated conjugated diene midblocks having a number average molecularweight from about 20,000 to about 170,000. The total number averagemolecular weight of the block polymer may be from about 30,000 to about250,000.

Particularly suitable thermoplastic elastomeric copolymers are availablefrom Kraton Polymers LLC of Houston, Tex. under the trade name KRATON®.KRATON® polymers include styrene-diene block copolymers, such asstyrene-butadiene, styrene-isoprene, styrene-butadiene-styrene, andstyrene-isoprene-styrene. KRATON® polymers also include styrene-olefinblock copolymers formed by selective hydrogenation of styrene-dieneblock copolymers. Examples of such styrene-olefin block copolymersinclude styrene-(ethylene-butylene), styrene-(ethylene-propylene),styrene-(ethylene-butylene)-styrene,styrene-(ethylene-propylene)-styrene,styrene-(ethylene-butylene)-styrene-(ethylene-butylene),styrene-(ethylene-propylene)-styrene-(ethylene-propylene), andstyrene-ethylene-(ethylene-propylene)-styrene. These block copolymersmay have a linear, radial or star-shaped molecular configuration.Specific KRATON® block copolymers include those sold under the brandnames G 1652, G 1657, G 1730, MD6673, and MD6973. Various suitablestyrenic block copolymers are described in U.S. Pat. Nos. 4,663,220,4,323,534, 4,834,738, 5,093,422 and 5,304,599, which are herebyincorporated in their entirety by reference thereto for all purposes.Other commercially available block copolymers include the S-EP-Selastomeric copolymers available from Kuraray Company, Ltd. of Okayama,Japan, under the trade designation SEPTON®. Still other suitablecopolymers include the S-I-S and S-B-S elastomeric copolymers availablefrom Dexco Polymers of Houston, Tex. under the trade designationVECTOR®. Also suitable are polymers composed of an A-B-A-B tetrablockcopolymer, such as discussed in U.S. Pat. No. 5,332,613 to Taylor, etal., which is incorporated herein in its entirety by reference theretofor all purposes. An example of such a tetrablock copolymer is astyrene-poly(ethylene-propylene)-styrene-poly(ethylene-propylene)(“S-EP-S-EP”) block copolymer.

The amount of elastomeric polymer(s) employed in the film may vary, butis typically about 30 wt. % or more of the film, in some embodimentsabout 50 wt. % or more, and in some embodiments, about 80 wt. % or moreof the of the film. In one embodiment, for example, the semi-crystallinepolyolefin(s) constitute about 70 wt. % or more of the film, in someembodiments about 80 wt. % or more of the film, and in some embodiments,about 90 wt. % or more of the film. In other embodiments, blends ofsemi-crystalline polyolefin(s) and elastomeric block copolymer(s) may beemployed. In such embodiments, the block copolymer(s) may constitutefrom about 5 wt. % to about 50 wt. %, in some embodiments from about 10wt. % to about 40 wt. %, and in some embodiments, from about 15 wt. % toabout 35 wt. % of the blend. Likewise, the semi-crystallinepolyolefin(s) may constitute from about 50 wt. % to about 95 wt. %, insome embodiments from about 60 wt. % to about 90 wt. %, and in someembodiments, from about 65 wt. % to about 85 wt. % of the blend. Itshould of course be understood that other elastomeric and/ornon-elastomeric polymers may also be employed in the film.

Besides polymers, the elastic film of the present invention may alsocontain other components as is known in the art. In one embodiment, forexample, the elastic film contains a filler. Fillers are particulates orother forms of material that may be added to the film polymer extrusionblend and that will not chemically interfere with the extruded film, butwhich may be uniformly dispersed throughout the film. Fillers may servea variety of purposes, including enhancing film opacity and/orbreathability (i.e., vapor-permeable and substantiallyliquid-impermeable). For instance, filled films may be made breathableby stretching, which causes the polymer to break away from the fillerand create microporous passageways. Breathable microporous elastic filmsare described, for example, in U.S. Pat. Nos. 5,997,981; 6,015,764; and6,111,163 to McCormack, et al.; 5,932,497 to Morman, et al.; 6,461,457to Taylor, et al., which are incorporated herein in their entirety byreference thereto for all purposes.

The fillers may have a spherical or non-spherical shape with averageparticle sizes in the range of from about 0.1 to about 7 microns.Examples of suitable fillers include, but are not limited to, calciumcarbonate, various kinds of clay, silica, alumina, barium carbonate,sodium carbonate, magnesium carbonate, talc, barium sulfate, magnesiumsulfate, aluminum sulfate, titanium dioxide, zeolites, cellulose-typepowders, kaolin, mica, carbon, calcium oxide, magnesium oxide, aluminumhydroxide, pulp powder, wood powder, cellulose derivatives, chitin andchitin derivatives. A suitable coating, such as stearic acid, may alsobe applied to the filler particles if desired. When utilized, the fillercontent may vary, such as from about 25 wt. % to about 75 wt. %, in someembodiments, from about 30 wt. % to about 70 wt. %, and in someembodiments, from about 40 wt. % to about 60 wt. % of the film.

Other additives may also be incorporated into the film, such as meltstabilizers, processing stabilizers, heat stabilizers, lightstabilizers, antioxidants, heat aging stabilizers, whitening agents,antiblocking agents, bonding agents, tackifiers, viscosity modifiers,etc. Examples of suitable tackifier resins may include, for instance,hydrogenated hydrocarbon resins. REGALREZ™ hydrocarbon resins areexamples of such hydrogenated hydrocarbon resins, and are available fromEastman Chemical. Other tackifiers are available from ExxonMobil underthe ESCOREZ™ designation. Viscosity modifiers may also be employed, suchas polyethylene wax (e.g., EPOLENE™ C-10 from Eastman Chemical).Phosphite stabilizers (e.g., IRGAFOS available from Ciba SpecialtyChemicals of Terrytown, N.Y. and DOVERPHOS available from Dover ChemicalCorp. of Dover, Ohio) are exemplary melt stabilizers. In addition,hindered amine stabilizers (e.g., CHIMASSORB available from CibaSpecialty Chemicals) are exemplary heat and light stabilizers. Further,hindered phenols are commonly used as an antioxidant in the productionof films. Some suitable hindered phenols include those available fromCiba Specialty Chemicals of under the trade name “Irganox®”, such asIrganox® 1076, 1010, or E 201. Moreover, bonding agents may also beadded to the film to facilitate bonding of the film to additionalmaterials (e.g., nonwoven web). When employed, such additives (e.g.,tackifier, antioxidant, stabilizer, etc.) may each be present in anamount from about 0.001 wt. % to about 25 wt. %, in some embodiments,from about 0.005 wt. % to about 20 wt. %, and in some embodiments, from0.01 wt. % to about 15 wt. % of the film.

The elastic film of the present invention may be mono- or multi-layered.Multilayer films may be prepared by co-extrusion of the layers,extrusion coating, or by any conventional layering process. Suchmultilayer films normally contain at least one base layer and at leastone skin layer, but may contain any number of layers desired. Forexample, the multilayer film may be formed from a base layer and one ormore skin layers, wherein the base layer is formed from asemi-crystalline polyolefin. In such embodiments, the skin layer(s) maybe formed from any film-forming polymer. If desired, the skin layer(s)may contain a softer, lower melting polymer or polymer blend thatrenders the layer(s) more suitable as heat seal bonding layers forthermally bonding the film to a nonwoven web. For example, the skinlayer(s) may be formed from an olefin polymer or blends thereof, such asdescribed above. Additional film-forming polymers that may be suitablefor use with the present invention, alone or in combination with otherpolymers, include ethylene vinyl acetate, ethylene ethyl acrylate,ethylene acrylic acid, ethylene methyl acrylate, ethylene normal butylacrylate, nylon, ethylene vinyl alcohol, polystyrene, polyurethane, andso forth.

The thickness of the skin layer(s) is generally selected so as not tosubstantially impair the elastomeric properties of the film. To thisend, each skin layer may separately comprise from about 0.5% to about15% of the total thickness of the film, and in some embodiments fromabout 1% to about 10% of the total thickness of the film. For instance,each skin layer may have a thickness of from about 0.1 to about 10micrometers, in some embodiments from about 0.5 to about 5 micrometers,and in some embodiments, from about 1 to about 2.5 micrometers.Likewise, the base layer may have a thickness of from about 1 to about40 micrometers, in some embodiments from about 2 to about 25micrometers, and in some embodiments, from about 5 to about 20micrometers.

The properties of the resulting film may generally vary as desired. Forinstance, prior to stretching, the film typically has a basis weight ofabout 100 grams per square meter or less, and in some embodiments, fromabout 50 to about 75 grams per square meter. Upon stretching, the filmtypically has a basis weight of about 60 grams per square meter or less,and in some embodiments, from about 15 to about 35 grams per squaremeter. The stretched film may also have a total thickness of from about1 to about 100 micrometers, in some embodiments, from about 10 to about80 micrometers, and in some embodiments, from about 20 to about 60micrometers.

II. Nonwoven Web Material

As will be described in more detail below, the polymers used to form thenonwoven web material typically have a softening temperature that ishigher than the temperature imparted during bonding. In this manner, thepolymers do not substantially soften during bonding to such an extentthat the fibers of the nonwoven web material become completely meltflowable. For instance, polymers may be employed that have a Vicatsoftening temperature (ASTM D-1525) of from about 100° C. to about 300°C., in some embodiments from about 120° C. to about 250° C., and in someembodiments, from about 130° C. to about 200° C. Exemplaryhigh-softening point polymers for use in forming nonwoven web materialsmay include, for instance, polyolefins, e.g., polyethylene,polypropylene, polybutylene, etc.; polytetrafluoroethylene; polyesters,e.g., polyethylene terephthalate and so forth; polyvinyl acetate;polyvinyl chloride acetate; polyvinyl butyral; acrylic resins, e.g.,polyacrylate, polymethylacrylate, polymethylmethacrylate, and so forth;polyamides, e.g., nylon; polyvinyl chloride; polyvinylidene chloride;polystyrene; polyvinyl alcohol; polyurethanes; polylactic acid;copolymers thereof; and so forth. If desired, biodegradable polymers,such as those described above, may also be employed. Synthetic ornatural cellulosic polymers may also be used, including but not limitedto, cellulosic esters; cellulosic ethers; cellulosic nitrates;cellulosic acetates; cellulosic acetate butyrates; ethyl cellulose;regenerated celluloses, such as viscose, rayon, and so forth. It shouldbe noted that the polymer(s) may also contain other additives, such asprocessing aids or treatment compositions to impart desired propertiesto the fibers, residual amounts of solvents, pigments or colorants, andso forth.

Monocomponent and/or multicomponent fibers may be used to form thenonwoven web material. Monocomponent fibers are generally formed from apolymer or blend of polymers extruded from a single extruder.Multicomponent fibers are generally formed from two or more polymers(e.g., bicomponent fibers) extruded from separate extruders. Thepolymers may be arranged in substantially constantly positioned distinctzones across the cross-section of the fibers. The components may bearranged in any desired configuration, such as sheath-core,side-by-side, pie, island-in-the-sea, three island, bull's eye, orvarious other arrangements known in the art. and so forth. Variousmethods for forming multicomponent fibers are described in U.S. Pat.Nos. 4,789,592 to Taniguchi et al. and U.S. Pat. No. 5,336,552 to Stracket al., U.S. Pat. No. 5,108,820 to Kaneko, et al., U.S. Pat. No.4,795,668 to Kruege, et al., U.S. Pat. No. 5,382,400 to Pike, et al.,U.S. Pat. No. 5,336,552 to Strack, et al., and U.S. Pat. No. 6,200,669to Marmon, et al., which are incorporated herein in their entirety byreference thereto for all purposes. Multicomponent fibers having variousirregular shapes may also be formed, such as described in U.S. Pat. Nos.5,277,976 to Hogle, et al., 5,162,074 to Hills, 5,466,410 to Hills,5,069,970 to Largman, et al., and 5,057,368 to Largman, et al., whichare incorporated herein in their entirety by reference thereto for allpurposes.

Although any combination of polymers may be used, the polymers of themulticomponent fibers are typically made from thermoplastic materialswith different glass transition or melting temperatures where a firstcomponent (e.g., sheath) melts at a temperature lower than a secondcomponent (e.g., core). Softening or melting of the first polymercomponent of the multicomponent fiber allows the multicomponent fibersto form a tacky skeletal structure, which upon cooling, stabilizes thefibrous structure. For example, the multicomponent fibers may have fromabout 20% to about 80%, and in some embodiments, from about 40% to about60% by weight of the low melting polymer. Further, the multicomponentfibers may have from about 80% to about 20%, and in some embodiments,from about 60% to about 40%, by weight of the high melting polymer. Someexamples of known sheath-core bicomponent fibers available from KoSaInc. of Charlotte, N.C. under the designations T-255 and T-256, both ofwhich use a polyolefin sheath, or T-254, which has a low meltco-polyester sheath. Still other known bicomponent fibers that may beused include those available from the Chisso Corporation of Moriyama,Japan or Fibervisions LLC of Wilmington, Del.

Fibers of any desired length may be employed, such as staple fibers,continuous fibers, etc. In one particular embodiment, for example,staple fibers may be used that have a fiber length in the range of fromabout 1 to about 150 millimeters, in some embodiments from about 5 toabout 50 millimeters, in some embodiments from about 10 to about 40millimeters, and in some embodiments, from about 10 to about 25millimeters. Although not required, carding techniques may be employedto form fibrous layers with staple fibers as is well known in the art.For example, fibers may be formed into a carded web by placing bales ofthe fibers into a picker that separates the fibers. Next, the fibers aresent through a combing or carding unit that further breaks apart andaligns the fibers in the machine direction so as to form a machinedirection-oriented fibrous nonwoven web. The carded web may then bebonded using known techniques to form a bonded carded nonwoven web.

If desired, the nonwoven web material used to form the nonwovencomposite may have a multi-layer structure. Suitable multi-layeredmaterials may include, for instance, spunbond/meltblown/spunbond (SMS)laminates and spunbond/meltblown (SM) laminates. Various examples ofsuitable SMS laminates are described in U.S. Pat. Nos. 4,041,203 toBrock et al.; 5,213,881 to Timmons, et al.; 5,464,688 to Timmons, etal.; 4,374,888 to Bornslaeger; 5,169,706 to Collier, et al.; and4,766,029 to Brock et al., which are incorporated herein in theirentirety by reference thereto for all purposes. In addition,commercially available SMS laminates may be obtained from Kimberly-ClarkCorporation under the designations Spunguard® and Evolution®.

Another example of a multi-layered structure is a spunbond web producedon a multiple spin bank machine in which a spin bank deposits fibersover a layer of fibers deposited from a previous spin bank. Such anindividual spunbond nonwoven web may also be thought of as amulti-layered structure. In this situation, the various layers ofdeposited fibers in the nonwoven web may be the same, or they may bedifferent in basis weight and/or in terms of the composition, type,size, level of crimp, and/or shape of the fibers produced. As anotherexample, a single nonwoven web may be provided as two or moreindividually produced layers of a spunbond web, a carded web, etc.,which have been bonded together to form the nonwoven web. Theseindividually produced layers may differ in terms of production method,basis weight, composition, and fibers as discussed above.

A nonwoven web material may also contain an additional fibrous componentsuch that it is considered a composite. For example, a nonwoven web maybe entangled with another fibrous component using any of a variety ofentanglement techniques known in the art (e.g., hydraulic, air,mechanical, etc.). In one embodiment, the nonwoven web is integrallyentangled with cellulosic fibers using hydraulic entanglement. A typicalhydraulic entangling process utilizes high pressure jet streams of waterto entangle fibers to form a highly entangled consolidated fibrousstructure, e.g., a nonwoven web. Hydraulically entangled nonwoven websof staple length and continuous fibers are disclosed, for example, inU.S. Pat. Nos. 3,494,821 to Evans and 4,144,370 to Boulton, which areincorporated herein in their entirety by reference thereto for allpurposes. Hydraulically entangled composite nonwoven webs of acontinuous fiber nonwoven web and a pulp layer are disclosed, forexample, in U.S. Pat. Nos. 5,284,703 to Everhart, et al. and 6,315,864to Anderson, et al., which are incorporated herein in their entirety byreference thereto for all purposes. The fibrous component of thecomposite may contain any desired amount of the resulting substrate. Thefibrous component may contain greater than about 50% by weight of thecomposite, and in some embodiments, from about 60% to about 90% byweight of the composite. Likewise, the nonwoven web may contain lessthan about 50% by weight of the composite, and in some embodiments, fromabout 10% to about 40% by weight of the composite.

Although not required, the nonwoven web material may necked in one ormore directions prior to lamination to the film of the presentinvention. Suitable techniques necking techniques are described in U.S.Pat. Nos. 5,336,545, 5,226,992, 4,981,747 and 4,965,122 to Morman, aswell as U.S. patent application Publication No. 2004/0121687 to Morman,et al. Alternatively, the nonwoven web may remain relativelyinextensible in at least one direction prior to lamination to the film.In such embodiments, the nonwoven web may be optionally stretched in oneor more directions subsequent to lamination to the film.

The basis weight of the nonwoven web material may generally vary, suchas from about 5 grams per square meter (“gsm”) to 120 gsm, in someembodiments from about 10 gsm to about 70 gsm, and in some embodiments,from about 15 gsm to about 35 gsm. When multiple nonwoven web materials,such materials may have the same or different basis weights.

III. Lamination Technique

To concurrently form apertures and bonds between the film and thenonwoven web material, lamination is generally accomplished in thepresent invention via a patterned bonding technique (e.g., thermal pointbonding, ultrasonic bonding, etc.) in which the materials are suppliedto a nip defined by at least one patterned roll. Thermal point bonding,for instance, typically employs a nip formed between two rolls, at leastone of which is patterned. Ultrasonic bonding, on the other hand,typically employs a nip formed between a sonic horn and a patternedroll. Regardless of the technique chosen, the patterned roll contains aplurality of raised bonding elements to concurrently bond the film tothe nonwoven web material(s) and form apertures in the film. The size ofthe bonding elements may be specifically tailored to facilitate theformation of apertures in the film and enhance bonding between the filmand the nonwoven material(s). For example, the bonding elements aretypically selected to have a relatively large length dimension. Thelength dimension of the bonding elements may be from about 300 to about5000 micrometers, in some embodiments from about 500 to about 4000micrometers, and in some embodiments, from about 1000 to about 2000micrometers. The width dimension of the bonding elements may likewiserange from about 20 to about 500 micrometers, in some embodiments fromabout 40 to about 200 micrometers, and in some embodiments, from about50 to about 150 micrometers. In addition, the “element aspect ratio”(the ratio of the length of an element to its width) may range fromabout 2 to about 100, in some embodiments from about 4 to about 50, andin some embodiments, from about 5 to about 20.

Besides the size of the bonding elements, the overall bonding patternmay also be selectively controlled to achieve the desired apertureformation. In one embodiment, for example, a bonding pattern is selectedin which the longitudinal axis (longest dimension along a center line ofthe element) of one or more of the bonding elements is skewed relativeto the machine direction (“MD”) of the elastic film. For example, one ormore of the bonding elements may be oriented from about 30° to about150°, in some embodiments from about 45° to about 135°, and in someembodiments, from about 60° to about 120° relative to the machinedirection of the film. In this manner, the bonding elements will presenta relatively large surface to the film in a direction substantiallyperpendicular to that which the film moves. This increases the area overwhich shear stress is imparted to the film and, in turn, facilitatesaperture formation.

The pattern of the bonding elements is generally selected so that thenonwoven composite has a total bond area of less than about 50% (asdetermined by conventional optical microscopic methods), and in someembodiments, less than about 30%. The bond density is also typicallygreater than about 50 bonds per square inch, and in some embodiments,from about 75 to about 500 pin bonds per square inch. One suitablebonding pattern for use in the present invention is known as an“S-weave” pattern and is described in U.S. Pat. No. 5,964,742 toMcCormack, et al., which is incorporated herein in its entirety byreference thereto for all purposes. S-weave patterns typically have abonding element density of from about 50 to about 500 bonding elementsper square inch, and in some embodiments, from about 75 to about 150bonding elements per square inch. An example of a suitable “S-weave”pattern in shown in FIG. 2, which illustrates S-shaped bonding elements88 having a length dimension “L” and a width dimension “W.” Anothersuitable bonding pattern is known as the “rib-knit” pattern and isdescribed in U.S. Pat. No. 5,620,779 to Levy, et al., which isincorporated herein in its entirety by reference thereto for allpurposes. Rib-knit patterns typically have a bonding element density offrom about 150 to about 400 bonding elements per square inch, and insome embodiments, from about 200 to about 300 bonding elements persquare inch. An example of a suitable “rib-knit” pattern in shown inFIG. 3, which illustrates bonding elements 89 and bonding elements 91,which are oriented in a different direction. Yet another suitablepattern is the “wire weave” pattern, which has a bonding element densityof from about 200 to about 500 bonding elements per square inch, and insome embodiments, from about 250 to about 350 bonding elements persquare inch. An example of a suitable “wire-weave” pattern in shown inFIG. 4, which illustrates bonding elements 93 and bonding elements 95,which are oriented in a different direction. Other bond patterns thatmay be used in the present invention are described in U.S. Pat. Nos.3,855,046 to Hansen et al.; 5,962,112 to Haynes et al.; 6,093,665 toSayovitz et al.; D375,844 to Edwards, et al.; D428,267 to Romano et al.;and D390,708 to Brown, which are incorporated herein in their entiretyby reference thereto for all purposes.

The selection of an appropriate bonding temperature (e.g., thetemperature of a heated roll) will help melt and/soften thelow-softening point elastomeric polymer(s) of the film at regionsadjacent to the bonding elements. The softened elastomeric polymer(s)may then flow and become displaced during bonding, such as by pressureexerted by the bonding elements. The displaced portions of the filmsurrounding the apertures can also fuse to the nonwoven web material(s),thereby forming an integral nonwoven composite. Furthermore, because theelastomeric polymer(s) may physically entrap or adhere to the fibers atthe bond sites, adequate bond formation may be achieved withoutrequiring substantial softening of the polymer(s) used to form thenonwoven web material. Thus, the nonwoven web material remainssubstantially unbonded to the film or other materials at those regionslocated directly adjacent to (e.g. above or below) the apertures.Further, the nonwoven web material is also generally unapertured,although it may of course develop some small cuts or tears duringprocessing.

To achieve such concurrent aperture and bond formation withoutsubstantially softening the polymer(s) of the nonwoven web material, thebonding temperature and pressure may be selectively controlled. Forexample, one or more rolls may be heated to a surface temperature offrom about 50° C. to about 160° C., in some embodiments from about 60°C. to about 140° C., and in some embodiments, from about 70° C. to about120° C. Likewise, the pressure exerted by rolls (“nip pressure”) duringthermal bonding may range from about 75 to about 600 pounds per linearinch, in some embodiments from about 100 to about 400 pounds per linearinch, and in some embodiments, from about 120 to about 200 pounds perlinear inch. Of course, the residence time of the materials mayinfluence the particular bonding parameters employed.

As stated, another factor that influences concurrent aperture and bondformation is the degree of tension in the film during lamination. Anincrease in film tension, for example, typically correlates to anincrease in aperture size. Of course, a film tension that is too highmay adversely affect the integrity of the film. Thus, in mostembodiments of the present invention, a stretch ratio of about 1.5 ormore, in some embodiments from about 2.5 to about 7.0, and in someembodiments, from about 3.0 to about 5.5, is employed to achieve thedesired degree of tension in the film during lamination. The stretchratio may be determined by dividing the final length of the film by itsoriginal length. The stretch ratio may also be approximately the same asthe draw ratio, which may be determined by dividing the linear speed ofthe film during lamination (e.g., speed of the nip rolls) by the linearspeed at which the film is formed (e.g., speed of casting rolls or blownnip rolls).

The film may be “pre-stretched” (prior to lamination) by rolls rotatingat different speeds of rotation so that the sheet is stretched to thedesired stretch ratio in the machine direction. This uniaxiallystretched film may also be oriented in the cross-machine direction toform a “biaxially stretched” film. The orientation temperature profileduring the “pre-stretching” operation is generally below the meltingpoint of one or more polymers in the film, but high enough to enable thecomposition to be drawn or stretched. For example, the film may bestretched at a temperature from about 15° C. to about 50° C., in someembodiments from about 25° C. to about 40° C., and in some embodiments,from about 30° C. to about 40° C. When “pre-stretched” in the mannerdescribed above, the degree of stretch during lamination may beincreased, maintained, or slightly reduced (retracted) to desired degreeof tension.

Upon lamination, the elastic film is bonded to the nonwoven webmaterial(s) and apertured. The size and/or pattern of the resultingapertures generally correspond to the size and/or pattern of the bondingelements. That is, the apertures may have a length, width, aspect ratio,and orientation as described above. For example, the length dimension ofthe apertures may be from about 200 to about 5000 micrometers, in someembodiments from about 350 to about 4000 micrometers, and in someembodiments, from about 500 to about 2500 micrometers. The widthdimension of the apertures may likewise range from about 20 to about 500micrometers, in some embodiments from about 40 to about 200 micrometers,and in some embodiments, from about 50 to about 150 micrometers. Inaddition, the “aspect ratio” (the ratio of the length of an aperture toits width) may range from about 2 to about 100, in some embodiments fromabout 4 to about 50, and in some embodiments, from about 5 to about 20.Similarly, the longitudinal axis of one or more of the apertures(longest dimension along a center line of the aperture) may be skewedrelative to the machine direction of the elastic film, such as fromabout 30° to about 150°, in some embodiments from about 45° to about135°, and in some embodiments, from about 60° to about 120° relative tothe machine direction of the film.

Various embodiments of the present invention will now be described ingreater detail. Of course, it should be understood that the descriptionprovided below is merely exemplary, and that other methods arecontemplated by the present invention. Referring to FIG. 1, forinstance, one embodiment of a method for forming a composite from anelastic film and a nonwoven web material is shown. As shown, the rawmaterials of the film (e.g., elastomeric polymer) may be dry mixedtogether (i.e., without a solvent) and added to a hopper (not shown) ofan extrusion apparatus 40. The raw materials may alternatively beblended with a solvent. In the hopper, the materials are dispersivelymixed in the melt and compounded using any known technique, such asbatch and/or continuous compounding techniques that employ, for example,a Banbury mixer, Farrel continuous mixer, single screw extruder, twinscrew extruder, etc.

Any known technique may be used to form a film from the compoundedmaterial, including blowing, casting, flat die extruding, etc. In oneparticular embodiment, the film may be formed by a blown process inwhich a gas (e.g., air) is used to expand a bubble of the extrudedpolymer blend through an annular die. The bubble is then collapsed andcollected in flat film form. Processes for producing blown films aredescribed, for instance, in U.S. Pat. Nos. 3,354,506 to Raley; 3,650,649to Schippers; and 3,801,429 to Schrenk et al., as well as U.S. patentapplication Publication Nos. 2005/0245162 to McCormack, et al. and2003/0068951 to Boggs. et al., all of which are incorporated herein intheir entirety by reference thereto for all purposes. For example, inthe particular embodiment of FIG. 1, the compounded material (not shown)is supplied to the extrusion apparatus 40 and then blown into nip rolls42 to form a single-layered precursor elastic film 10. The rolls 42 maybe kept at temperature sufficient to solidify and quench the precursorelastic film 10 as it is formed, such as from about 20 to 60° C.Typically, the resulting precursor elastic film is generallyunapertured, although it may of course possess small cuts or tears as aresult of processing. The use of an initially unapertured film canprovide a variety of benefits, including the avoidance of registrationsteps needed to align the apertures with bond sites during lamination.

Referring again to FIG. 1, one method for forming a uniaxially stretchedfilm is shown. In the illustrated embodiment, the film 10 is stretchedand thinned in the machine direction by passing it through afilm-orientation unit or machine direction orienter (“MDO”) 44, such ascommercially available from Marshall and Willams, Co. of Providence,R.I. In the illustrated embodiment, the MDO has a plurality ofstretching rolls 46 that progressively stretch and thin the film 10 inthe machine direction. While four pairs of rolls 46 are illustrated inFIG. 1, it should be understood that the number of rolls may be higheror lower, depending on the level of stretch that is desired and thedegrees of stretching between each roll. The film 10 may be stretched ineither single or multiple discrete stretching operations. The film 10may also be stretched in other directions. For example, the film may beclamped at its lateral edges by chain clips and conveyed into a tenteroven. In the tenter oven, the film may be drawn in the cross-machinedirection to the desired stretch ratio by chain clips diverged in theirforward travel.

A nonwoven web material is also employed for laminating to the elasticfilm 10. For example, the nonwoven web material may simply be unwoundfrom a supply roll. Alternatively, as shown in FIG. 1, a nonwoven webmaterial 30 may be formed in-line, such as by spunbond extruders 48. Theextruders 48 deposit fibers 50 onto a forming wire 52, which is part ofa continuous belt arrangement that circulates around a series of rolls.If desired, a vacuum (not shown) may be utilized to maintain the fiberson the forming wire 52. The spunbond fibers 50 form a mat 54 that mayoptionally be compressed via compaction rolls 56. Although notnecessarily required, a second material 30 a originating from a supplyroll 62 may also be laminated to the elastic film 10. The secondmaterial 30 a may be a second nonwoven web material, film, etc.

Regardless, thermal bonding techniques are employed to laminate thematerial(s) to the elastic film. In FIG. 1, for instance, the materials30 and 30 a are directed to a nip defined between rolls 58 forlaminating to the elastic film 10. One or both of the rolls 58 maycontain a plurality of raised bonding elements and/or may be heated.Upon lamination, the elastic film 10 is melt fused to the nonwoven webmaterials 30 and 30 a at a plurality of discrete bond sites 31. (SeeFIG. 7). That is, the elastomeric polymer(s) of the film 10 are softenedand/or melted so that they may physically entrap fibers of the nonwovenweb materials 30 and 30 a. Of course, the elastic film 10 may possess acertain tack so that it also adheres to the fibers upon lamination. Asshown in FIG. 7, the bond sites 31 may be located proximate (adjacent ornear to) a perimeter 37 defined by corresponding apertures 33, which areformed by displacement of the film 10. The particular location of thebond sites 31 adjacent to or near the apertures 33 may enhance theintegrity of the resulting composite 32 by strengthening the areasurrounding the apertures 33. Because thermal bonding occurs at atemperature that is insufficient to substantially soften the polymer(s)of the nonwoven web materials 30 and 30 a, as described above, they arenot substantially melt fused to each other. In this manner, thecomposite 32 may better retain the physical properties (e.g., liquidpermeability, softness, bulk, and hand feel) of the individual nonwovenweb materials.

The resulting composite 32 may then be wound and stored on a take-uproll 60. Optionally, the composite 32 is kept under tension, such as byusing the same linear velocity for the roll 60 as the speed of one ormore of the stretching rolls 46. More preferably, however, the composite32 is allowed to slightly retract prior to winding on to the take-uproll 60. This may be achieved by using a slower linear velocity for theroll 60. Because the elastic film 10 is tensioned prior to lamination,it will retract toward its original machine direction length and becomeshorter in the machine direction, thereby buckling or forming gathers inthe composite. The resulting elastic composite thus becomes extensiblein the machine direction to the extent that the gathers or buckles inthe web may be pulled back out flat and allow the elastic film 10 toelongate.

While not shown in FIG. 1, various additional potential processingand/or finishing steps known in the art, such as slitting, treating,printing graphics, etc., may be performed without departing from thespirit and scope of the invention. For instance, the composite mayoptionally be mechanically stretched in the cross-machine and/or machinedirections to enhance extensibility. In one embodiment, the compositemay be coursed through two or more rolls that have grooves in the CDand/or MD directions. Such grooved satellite/anvil roll arrangements aredescribed in U.S. patent application Publication Nos. 2004/0110442 toRhim, et al. and 2006/0151914 to Gerndt, et al., which are incorporatedherein in their entirety by reference thereto for all purposes. Forinstance, the laminate may be coursed through two or more rolls thathave grooves in the CD and/or MD directions. The grooved rolls may beconstructed of steel or other hard material (such as a hard rubber).

FIGS. 5-6 further illustrate the manner in which groove rolls mayincrementally stretch the composite. As shown, for example, satelliterolls 182 may engage an anvil roll 184, each of which include aplurality of ridges 183 defining a plurality of grooves 185 positionedacross the grooved rolls in the cross-machine direction. The grooves 185are generally oriented perpendicular to the direction of stretch of thematerial. In other words, the grooves 185 are oriented in the machinedirection to stretch the composite in the cross-machine direction. Thegrooves 185 may likewise be oriented in the cross-machine direction tostretch the composite in the machine direction. The ridges 183 ofsatellite roll 182 intermesh with the grooves 185 of anvil roll 184, andthe grooves 185 of satellite roll 182 intermesh with the ridges 183 ofanvil roll 184.

The dimensions and parameters of the grooves 185 and ridges 183 may havea substantial effect on the degree of extensibility provided by therolls 182 and 184. For example, the number of grooves 185 contained on aroll may generally range from about 3 and 15 grooves per inch, in someembodiments from about 5 and 12 grooves per inch, and in someembodiments, from about 5 and 10 grooves per inch. The grooves 185 mayalso have a certain depth “D”, which generally ranges from about 0.25 toabout 1.0 centimeter, and in some embodiments, from about 0.4 to about0.6 centimeters. In addition, the peak-to-peak distance “P” between thegrooves 185 is typically from about 0.1 to about 0.9 centimeters, and insome embodiments, from about 0.2 to about 0.5 centimeters. Also, thegroove roll engagement distance “E” between the grooves 185 and ridges183 may be up to about 0.8 centimeters, and in some embodiments, fromabout 0.15 to about 0.4 centimeters. Regardless, the composite 32 (FIG.6) may be stretched in one or more directions at a stretch ratio of fromabout 1.5 to about 8.0, in some embodiments by at least about 2.0 toabout 6.0, and in some embodiments, from about 2.5 to about 4.5. Ifdesired, heat may be applied to the composite just prior to or duringthe application of incremental stretch to cause it to relax somewhat andease extension. Heat may be applied by any suitable method known in theart, such as heated air, infrared heaters, heated nipped rolls, orpartial wrapping of the laminate around one or more heated rolls orsteam canisters, etc. Heat may also be applied to the grooved rollsthemselves. It should also be understood that other grooved rollarrangement are equally suitable, such as two grooved rolls positionedimmediately adjacent to one another.

Besides the above-described grooved rolls, other techniques may also beused to mechanically stretch the composite in one or more directions.For example, the composite may be passed through a tenter frame thatstretches the composite. Such tenter frames are well known in the artand described, for instance, in U.S. patent application Publication No.2004/0121687 to Morman, et al. The composite may also be necked.Suitable techniques necking techniques are described in U.S. Pat. Nos.5,336,545, 5,226,992, 4,981,747 and 4,965,122 to Morman, as well as U.S.patent application Publication No. 2004/0121687 to Morman, et al., allof which are incorporated herein in their entirety by reference theretofor all purposes.

The nonwoven composite of the present invention may be used in a widevariety of applications. As noted above, for example, the nonwovencomposite may be used in an absorbent article. An “absorbent article”generally refers to any article capable of absorbing water or otherfluids. Examples of some absorbent articles include, but are not limitedto, personal care absorbent articles, such as diapers, training pants,absorbent underpants, incontinence articles, feminine hygiene products(e.g., sanitary napkins), swim wear, baby wipes, and so forth; medicalabsorbent articles, such as garments, fenestration materials, underpads,bedpads, bandages, absorbent drapes, and medical wipes; food servicewipers; clothing articles; and so forth. Materials and processessuitable for forming such absorbent articles are well known to thoseskilled in the art. Absorbent articles may include a substantiallyliquid-impermeable layer (e.g., outer cover), a liquid-permeable layer(e.g., bodyside liner, surge layer, etc.), and an absorbent core.

In one particular embodiment, the nonwoven composite of the presentinvention may be used to form a liquid-permeable layer (e.g., bodysideliner, surge layer) of the absorbent article. As described above, theelastic film is bonded to the nonwoven web material at discrete bondsites located proximate to the perimeter of the apertures. Byselectively controlling the conditions of the lamination process,however, the nonwoven web material remains substantially unbonded (e.g.,not substantially melt fused together) at the regions located adjacentto the apertures. For example, when the elastic film is positionedbetween two nonwoven web materials, melt bond sites are not generallyformed between the nonwoven web materials at those regions adjacent tothe apertures. The conditions of the lamination process may also allowthe nonwoven web material(s) to remain generally unapertured at thoseregions adjacent to the apertures in the elastic film. The existence ofsuch generally unbonded and unapertured regions in the nonwoven webmaterial(s) enhances the ability of the composite to be employed as aliquid-permeable layer in an absorbent article. Namely, because thenonwoven web material is not fused together at those regions adjacent tothe film apertures, a liquid may more readily flow through the nonwovenweb material and into the aperture. Likewise, the absence of substantialaperturing in the nonwoven web material allows it to retain otherdesirable properties (e.g., bulk, softness, handfeel, etc.).

Besides liquid-permeable materials (e.g., liners, surge layers, etc.),the nonwoven composite of the present invention may have a wide varietyof other uses, such as in providing an elastic waist, legcuff/gasketing, stretchable ear, side panel, outer cover, or any othercomponent in which elastic properties are desirable.

Various embodiments of an absorbent article that may be formed accordingto the present invention will now be described in more detail. Forpurposes of illustration only, an absorbent article is shown in FIG. 8as a diaper 201. However, as noted above, the invention may be embodiedin other types of absorbent articles, such as incontinence articles,sanitary napkins, diaper pants, feminine napkins, children's trainingpants, and so forth. In the illustrated embodiment, the diaper 201 isshown as having an hourglass shape in an unfastened configuration.However, other shapes may of course be utilized, such as a generallyrectangular shape, T-shape, or I-shape. As shown, the diaper 201includes a chassis 202 formed by various components, including an outercover 217, bodyside liner 205, absorbent core 203, and surge layer 207.It should be understood, however, that other layers may also be used inthe present invention. Likewise, one or more of the layers referred toin FIG. 8 may also be eliminated in certain embodiments of the presentinvention.

The bodyside liner 205 is generally employed to help isolate thewearer's skin from liquids held in the absorbent core 203. For example,the liner 205 presents a bodyfacing surface that is typically compliant,soft feeling, and non-irritating to the wearer's skin. Typically, theliner 205 is also less hydrophilic than the absorbent core 203 so thatits surface remains relatively dry to the wearer. As indicated above,the liner 205 may be liquid-permeable to permit liquid to readilypenetrate through its thickness. Exemplary liner constructions thatcontain a nonwoven web are described in U.S. Pat. Nos. 5,192,606 toProxmire, et al.; 5,702,377 to Collier, IV, et al.; 5,931,823 to Stokes,et al.; 6,060,638 to Paul, et al.; and 6,150,002 to Varona, as well asU.S. patent application Publication Nos. 2004/0102750 to Jameson;2005/0054255 to Morman, et al.; and 2005/0059941 to Baldwin, et al., allof which are incorporated herein in their entirety by reference theretofor all purposes. In one particular embodiment, the liner includes thenonwoven composite of the present invention.

As illustrated in FIG. 8, the diaper 201 may also include a surge layer207 that helps to decelerate and diffuse surges or gushes of liquid thatmay be rapidly introduced into the absorbent core 203. Desirably, thesurge layer 207 rapidly accepts and temporarily holds the liquid priorto releasing it into the storage or retention portions of the absorbentcore 203. In the illustrated embodiment, for example, the surge layer207 is interposed between an inwardly facing surface 216 of the bodysideliner 205 and the absorbent core 203. Alternatively, the surge layer 207may be located on an outwardly facing surface 218 of the bodyside liner205. The surge layer 207 is typically constructed from highlyliquid-permeable materials. Examples of suitable surge layers aredescribed in U.S. Pat. No. 5,486,166 to Ellis, et al. and U.S. Pat. No.5,490,846 to Ellis, et al., which are incorporated herein in theirentirety by reference thereto for all purposes. In one particularembodiment, the surge layer 207 includes the nonwoven composite of thepresent invention.

The outer cover 217 is typically formed from a material that issubstantially impermeable to liquids. For example, the outer cover 217may be formed from a thin plastic film or other flexibleliquid-impermeable material. In one embodiment, the outer cover 217 isformed from a polyethylene film having a thickness of from about 0.01millimeter to about 0.05 millimeter. The film may be impermeable toliquids, but permeable to gases and water vapor (i.e., “breathable”).This permits vapors to escape from the absorbent core 203, but stillprevents liquid exudates from passing through the outer cover 217. If amore cloth-like feeling is desired, the outer cover 217 may be formedfrom a polyolefin film laminated to a nonwoven web. For example, astretch-thinned polypropylene film may be thermally laminated to aspunbond web of polypropylene fibers.

Besides the above-mentioned components, the diaper 201 may also containvarious other components as is known in the art. For example, the diaper201 may also contain a substantially hydrophilic tissue wrapsheet (notillustrated) that helps maintain the integrity of the fibrous structureof the absorbent core 203. The tissue wrapsheet is typically placedabout the absorbent core 203 over at least the two major facing surfacesthereof, and composed of an absorbent cellulosic material, such ascreped wadding or a high wet-strength tissue. The tissue wrapsheet maybe configured to provide a wicking layer that helps to rapidlydistribute liquid over the mass of absorbent fibers of the absorbentcore 203. The wrapsheet material on one side of the absorbent fibrousmass may be bonded to the wrapsheet located on the opposite side of thefibrous mass to effectively entrap the absorbent core 203. Furthermore,the diaper 201 may also include a ventilation layer (not shown) that ispositioned between the absorbent core 203 and the outer cover 217. Whenutilized, the ventilation layer may help insulate the outer cover 217from the absorbent core 203, thereby reducing dampness in the outercover 217. Examples of such ventilation layers may include a nonwovenweb laminated to a breathable film, such as described in U.S. Pat. No.6,663,611 to Blaney, et al., which is incorporated herein in itsentirety by reference thereto for all purposes.

In some embodiments, the diaper 201 may also include a pair of sidepanels (or ears) (not shown) that extend from the side edges 232 of thediaper 201 into one of the waist regions. The side panels may beintegrally formed with a selected diaper component. For example, theside panels may be integrally formed with the outer cover 217 or fromthe material employed to provide the top surface. In alternativeconfigurations, the side panels may be provided by members connected andassembled to the outer cover 217, the top surface, between the outercover 217 and top surface, or in various other configurations. Ifdesired, the side panels may be elasticized or otherwise renderedelastomeric by use of the elastic nonwoven composite of the presentinvention. Examples of absorbent articles that include elasticized sidepanels and selectively configured fastener tabs are described in PCTPatent Application WO 95/16425 to Roessler; U.S. Pat. No. 5,399,219 toRoessler et al.; U.S. Pat. No. 5,540,796 to Fries; and U.S. Pat. No.5,595,618 to Fries, each of which is incorporated herein in its entiretyby reference thereto for all purposes.

As representatively illustrated in FIG. 8, the diaper 201 may alsoinclude a pair of containment flaps 212 that are configured to provide abarrier and to contain the lateral flow of body exudates. Thecontainment flaps 212 may be located along the laterally opposed sideedges 232 of the bodyside liner 205 adjacent the side edges of theabsorbent core 203. The containment flaps 212 may extend longitudinallyalong the entire length of the absorbent core 203, or may only extendpartially along the length of the absorbent core 203. When thecontainment flaps 212 are shorter in length than the absorbent core 203,they may be selectively positioned anywhere along the side edges 232 ofdiaper 201 in a crotch region 210. In one embodiment, the containmentflaps 212 extend along the entire length of the absorbent core 203 tobetter contain the body exudates. Such containment flaps 212 aregenerally well known to those skilled in the art. For example, suitableconstructions and arrangements for the containment flaps 212 aredescribed in U.S. Pat. No. 4,704,116 to Enloe, which is incorporatedherein in its entirety by reference thereto for all purposes.

To provide improved fit and to help reduce leakage of body exudates, thediaper 201 may be elasticized with suitable elastic members, as furtherexplained below. For example, as representatively illustrated in FIG. 8,the diaper 201 may include leg elastics 206 constructed to operablytension the side margins of the diaper 201 to provide elasticized legbands which can closely fit around the legs of the wearer to reduceleakage and provide improved comfort and appearance. Waist elastics 208may also be employed to elasticize the end margins of the diaper 201 toprovide elasticized waistbands. The waist elastics 208 are configured toprovide a resilient, comfortably close fit around the waist of thewearer. The elastic nonwoven composite of the present invention issuitable for use as the leg elastics 206 and waist elastics 208.Exemplary of such materials are laminate sheets that either comprise orare adhered to the outer cover 217 so that that elastic constrictiveforces are imparted thereto.

The diaper 201 may also include one or more fasteners 230. For example,two flexible fasteners 230 are illustrated in FIG. 8 on opposite sideedges of waist regions to create a waist opening and a pair of legopenings about the wearer. The shape of the fasteners 230 may generallyvary, but may include, for instance, generally rectangular shapes,square shapes, circular shapes, triangular shapes, oval shapes, linearshapes, and so forth. The fasteners may include, for instance, ahook-and-loop material, buttons, pins, snaps, adhesive tape fasteners,cohesives, fabric-and-loop fasteners, etc. In one particular embodiment,each fastener 230 includes a separate piece of hook material affixed tothe inside surface of a flexible backing.

The various regions and/or components of the diaper 201 may be assembledtogether using any known attachment mechanism, such as adhesive,ultrasonic, thermal bonds, etc. Suitable adhesives may include, forinstance, hot melt adhesives, pressure-sensitive adhesives, and soforth. When utilized, the adhesive may be applied as a uniform layer, apatterned layer, a sprayed pattern, or any of separate lines, swirls ordots. In the illustrated embodiment, for example, the outer cover 217and bodyside liner 205 are assembled to each other and to the absorbentcore 203 using an adhesive. Alternatively, the absorbent core 203 may beconnected to the outer cover 217 using conventional fasteners, such asbuttons, hook and loop type fasteners, adhesive tape fasteners, and soforth. Similarly, other diaper components, such as the leg elasticmembers 206, waist elastic members 208 and fasteners 230, may also beassembled into the diaper 201 using any attachment mechanism.

Although various configurations of a diaper have been described above,it should be understood that other diaper and absorbent articleconfigurations are also included within the scope of the presentinvention. In addition, the present invention is by no means limited todiapers. In fact, any other absorbent article may be formed inaccordance with the present invention, including, but not limited to,other personal care absorbent articles, such as training pants,absorbent underpants, adult incontinence products, feminine hygieneproducts (e.g., sanitary napkins), swim wear, baby wipes, and so forth;medical absorbent articles, such as garments, fenestration materials,underpads, bandages, absorbent drapes, and medical wipes; food servicewipers; clothing articles; and so forth. Several examples of suchabsorbent articles are described in U.S. Pat. Nos. 5,649,916 to DiPalma,et al.; 6,110,158 to Kielpikowski; 6,663,611 to Blaney, et al., whichare incorporated herein in their entirety by reference thereto for allpurposes. Still other suitable articles are described in U.S. patentapplication Publication No. 2004/0060112 A1 to Fell et al., as well asU.S. Pat. Nos. 4,886,512 to Damico et al.; 5,558,659 to Sherrod et al.;6,888,044 to Fell et al.; and 6,511,465 to Freiburger et al., all ofwhich are incorporated herein in their entirety by reference thereto forall purposes.

The present invention may be better understood with reference to thefollowing examples.

Test Methods

Cycle Testing

The materials were tested using a cyclical testing procedure todetermine load loss and percent set. In particular, 1-cycle testing wasutilized to 150% defined elongation. For this test, the sample size was3 inches in the cross-machine direction by 6 inches in the machinedirection. The Grip size was 3 inches in width. The grip separation was4 inches. The samples were loaded such that the machine direction of thesample was in the vertical direction. A preload of approximately 10 to15 grams was set. The test pulled the sample to 100% elongation at aspeed of 20 inches per minute, and then immediately (without pause)returned to the zero at a speed of 20 inches per minute. The results ofthe test data are all from the first cycle. The testing was done on aSintech Corp. constant rate of extension tester 2/S with a Renew MTSmongoose box (control) using TESTWORKS 4.07b software (Sintech Corp, ofCary, N.C.). The tests were conducted under ambient conditions.

Air Permeability:

Air permeability was determined using the “Frazier permeability”, whichis measured as standard cubic feet per minute of air flow across amaterial, per square foot of material with an air pressure differentialof 0.5 inches of water (125 Pa) across the sample. The test wasperformed at ambient conditions.

Peel Strength:

Values for peel strength were obtained using a specified width offabric, clamp jaw width and a constant rate of extension. This test usedtwo clamps, each having two jaws with each jaw having a facing incontact with the sample, to hold the material in the same plane, usuallyvertically, separated by 2 inches to start. The sample size was either 4inches in width (Example 1) or 3 inches (Example 1), and had as muchlength as necessary to delaminate enough sample length. The jaw facingsize was 1 inch high by at least 4 inches wide, and the constant rate ofextension is 300 mm/min. The sample was delaminated by hand a sufficientamount to allow it to be clamped into position and the clamps move apartat the specified rate of extension to pull the laminate apart. Thesample specimen was pulled apart at 180° of separation between the twolayers and the peel strength reported as an average of peak load ingrams. Measurement of the force was begun when 16 mm of the laminate hasbeen pulled apart and continued until a total of 170 mm has beendelaminated. The system may employ a MTS SYNERGY 200 Tensile Tester andTESTWORKS 4.08B software, which are available from MTS SystemsCorporation of Eden Prairie, Minn. Results were reported as an averageof three specimens and may be performed with the specimen in the crossdirection (CD) or the machine direction (MD). Testing was performed atambient conditions.

Strain:

The materials were tested to determine elongation or strain. For thistest, the sample size was 3 inches in the cross-machine direction by 7inches in the machine direction. The grip size was 3 inches in width,and intermeshing grips were utilized so that material would not slipwhile tested. The grip separation was 4 inches. The samples were loadedsuch that the machine direction of the sample was in the verticaldirection. A preload of approximately 10 to 15 grams was set. The testpulled the sample until 2000 grams of tension was produced, and then thetest stopped. The test speed was 500 millimeters per minute of extensionor strain. The test reported the elongation or strain in percent fromstart when 2000 grams of tension was produced in the material. Thetesting was done on a Sintech Corp. constant rate of extension tester2/S with a Renew MTS mongoose box (controller) using TESTWORKS 4.07bsoftware (Sintech Corp, of Cary, N.C.). The tests were conducted underambient conditions.

EXAMPLE 1

The ability to form an elastic nonwoven composite was demonstrated. Theelastic film was formed from 93 wt. % of EXACT™ 5361 (ExxonMobilChemical Co.), 5 wt. % of Dow Polyethylene 6401 (Dow Chemical Co.), and2 wt. % of SCC116921 pigment (Standridge Color Corp.). EXACT™ 5361 is ametallocene-catalyzed polyethylene plastomer having a density of 0.86grams per cubic centimeter, a peak melting temperature of 36° C., and amelt index of 3.0 grams per 10 minutes (190° C., 2.16 kg). DowPolyethylene 6401 is a low density polyethylene having a density of0.9215 grams per cubic centimeter, a melting point of 111° C., and amelt index of 2.0 grams per 10 minutes (190° C., 2.16 kg). The SCC116921pigment contained titanium dioxide blended with polypropylene andpolypropylene random copolymers.

The polymers were compounded by weighing appropriate portions of pelletsof each polymer, combining them into one container, and mixing themtogether by stirring. After compounding, the film samples were blownbetween a collapsing nip (operated at 38 feet per minute) so that a melttemperature of about 375° F. was achieved. The blown film was thermallybonded between two polypropylene spunbond facings having a basis weightof approximately about 14 grams per square meter. Specifically, the filmand facings were fed between an anvil and patterned roll (rib-knit). Thepatterned roll was heated to a roll surface temperature of 184° F., theanvil roll was heated to a roll surface temperature of 193° F., and thepressure was 157 pounds per linear inch. The rolls operated at a speedof 182 feet per minute so that the film was stretched in the machinedirection at a stretch ratio of 4.8 (i.e., 4.8 times its originallength). Once formed, the composite was then introduced into a nip ofintermeshing grooved steel rolls, such as shown in FIGS. 5-6, to stretchthe composite in the cross machine direction. The grooved steel rollswere heated to a temperature of 125° F. Finally, the composite wastransferred to a winder, which operated at a speed of 81 feet per minuteto allow in the composite to retract. The final basis weight wasapproximately 105 grams per square meter.

FIGS. 9-17 show scanning electron microphotographs of the resultingsample. FIG. 9, for instance, shows the approximately rectangularapertures 333 a formed by the bars of the rib-knit pattern (See e.g.,FIG. 3), while FIG. 10 shows the approximately circular apertures 333 bformed by the pins of the rib-knit pattern. A perspective view of theapertures is shown in FIG. 11. The apertures 333 are also shown in FIGS.14-17. In addition to illustrating apertures, the microphotographs alsoevidence the melt fusion of the elastic film to the fibers of thenonwoven webs. For instance, FIGS. 12-13 show an elastic film 310 thatis melt fused to a nonwoven web 330 at discrete bond sites 331. The bondsites 331 are proximately located to a perimeter 337 defined byapertures 333.

EXAMPLE 2

The ability to form an elastic nonwoven composite was demonstrated. Theelastic film was formed from 71 wt. % of EXACT™ 5361 (ExxonMobilChemical Co.), 25 wt. % KRATON® MD6673 (Kraton Polymers, LLC of HoustonTex.), and 2 wt. % of a SCC116921 pigment (Standridge Color Corp.).KRATON® MD6673 contains 68 wt. % of a styrene-ethylene-butylene-styreneblock copolymer (KRATON® MD6937), 20 wt. % REGALREZ™ 1126 (EastmanChemical) and 12 wt. % EPOLENE™ C-10 polyethylene wax (EastmanChemical). The SCC116921 pigment contained titanium dioxide blended withpolypropylene and polypropylene random copolymers. The polymers werecompounded by weighing appropriate portions of pellets of each polymer,combining them into one container, and mixing them together by stirring.

After compounding, the polymer composition was extruded at a melttemperature of 403° F. and cast onto a chill roll (set to a temperatureof 21° C.) operating at a speed of about 45 feet per minute. The filmwas then thermally bonded between two polypropylene spunbond facingshaving a basis weight of approximately about 14 grams per square meter.Specifically, the film and facings were fed between an anvil andpatterned roll (rib-knit). The patterned roll was heated to a rollsurface temperature of 230° F., the anvil roll was heated to a rollsurface temperature of 242° F., and the pressure was 176 pounds perlinear inch. The rolls operated at a speed of 147 feet per minute sothat the film was stretched in the machine direction at a stretch ratioof about 3.3 (i.e., 3.3 times its original length). Once formed, thecomposite was then introduced into a nip of intermeshing grooved steelrolls, such as shown in FIGS. 5-6, to stretch the composite in the crossmachine direction. The grooved steel rolls were heated to a temperatureof 125° F. Finally, the composite was transferred to a winder, whichoperated at a speed of 74 feet per minute to allow in the composite toretract. The final basis weight was approximately 100 grams per squaremeter.

EXAMPLE 3

The ability to form an elastic nonwoven composite was demonstrated. Theelastic film was formed from 98 wt. % of EXACT™ 5361 (ExxonMobilChemical Co.) and 2 wt. % of Dow Polyethylene 6401 (Dow Chemical Co.).The polymers were compounded by weighing appropriate portions of pelletsof each polymer, combining them into one container, and mixing themtogether by stirring. After compounding, the film samples were blownbetween a collapsing nip (operated at 30 feet per minute) so that a melttemperature of about 386° F. was achieved. The blown film was thermallybonded between two polypropylene spunbond facings having a basis weightof approximately about 17 grams per square meter. Specifically, the filmand facings were fed between an anvil and patterned roll (S-weave). Thepatterned roll was heated to a roll surface temperature of 211° F., theanvil roll was heated to a roll surface temperature of 203° F., and thepressure was 117 pounds per linear inch. The rolls operated at a speedof 110 feet per minute so that the film was stretched in the machinedirection at a stretch ratio of about 3.7 (i.e., 3.7 times its originallength). Once formed, the composite was then transferred to a winder,which operated at a speed of 70 feet per minute to allow in thecomposite to retract. The final basis weight was approximately 88 gramsper square meter.

EXAMPLE 4

The ability to form an elastic nonwoven composite was demonstrated. Theelastic film was formed from 93 wt. % of VISTAMAXX™ 1100 (ExxonMobilChemical Co.); 4 wt. % of Dow Polyethylene 6401 (Dow Chemical Co.); and3 wt. % of a SCC116921 pigment (Standridge Color Corp.). The SCC116921pigment contained titanium dioxide blended with polypropylene andpolypropylene random copolymers. The polymers were compounded byweighing appropriate portions of pellets of each polymer, combining theminto one container, and mixing them together by stirring. Aftercompounding, the film samples were blown between a collapsing nip(operated at 38 feet per minute) so that a melt temperature of about390° F. was achieved. The blown film was thermally bonded between twopolypropylene spunbond facings having a basis weight of approximatelyabout 14 grams per square meter. Specifically, the film and facings werefed between an anvil and patterned roll (rib-knit). The patterned rollwas heated to a roll surface temperature of 193° F., the anvil roll washeated to a roll surface temperature of 203° F., and the pressure was117 pounds per linear inch. The rolls operated at a speed of 210 feetper minute so that the film was stretched in the machine direction at astretch ratio of about 5.5 (i.e., 5.5 times its original length). Onceformed, the composite was then introduced into a nip of intermeshinggrooved steel rolls, such as shown in FIGS. 5-6, to stretch thecomposite in the cross machine direction. The grooved steel rolls wereheated to a temperature of 125° F. Finally, the composite wastransferred to a winder, which operated at a speed of 79 feet per minuteto allow in the composite to retract. The final basis weight wasapproximately 98 grams per square meter.

EXAMPLE 5

The elasticity (e.g., cycle testing), air permeability, peel strength,and strain of the composites of Examples 1-4 were tested. The resultsare set forth below in Tables 1 and 2.

TABLE 1 Cycle Testing of the Samples Cycle 1 Up Up Up Up Up Down DownDown Down Down Hyst. Imm. 50% 75% 100% 125% 150% 50% 75% 100% 125% 150%Loss Set Example (g_(f)) (g_(f)) (g_(f)) (g_(f)) (g_(f)) (g_(f)) (g_(f))(g_(f)) (g_(f)) (g_(f)) (%) (%) 1 452 617 800 1129 2473 63 141 241 4211641 67.5 31.4 2 385 — — — — — — — — — — — 3 846 — — — — — — — — — — — 4669 921 1136 1388 1720 148 243 359 572 1407 62.9 17.1

TABLE 2 Porosity and Mechanical Properties of the Samples AirPermeability MD Peel Strength Strain at 200 g_(f) Ex. (ft³/min)(g_(f)/inch) (%) 1 190.0 31.8 148 2 181.7 — 115 3 243.3 — 56 4 9.0 73.0156

As indicated above, the composites of the present invention exhibitedelastic characteristics, while also maintaining good air flow andmechanical properties.

While the invention has been described in detail with respect to thespecific embodiments thereof, it will be appreciated that those skilledin the art, upon attaining an understanding of the foregoing, mayreadily conceive of alterations to, variations of, and equivalents tothese embodiments. Accordingly, the scope of the present inventionshould be assessed as that of the appended claims and any equivalentsthereto.

1. A method of forming a nonwoven composite, the method comprising:Forming an elastic film from a polymer composition, Passing the film anda nonwoven web material through a nip formed by two rolls, at least oneof which is patterned with raised bonding elements, wherein the film isunder tension at a stretch ratio of from about 2.5 to about 7.0 at thenip, and wherein the nonwoven web material contains a polyolefin havinga Vicat softening temperature of from about 130° C. to about 200° C. andfurther wherein at least one of the rolls is heated to a temperature offrom about 50° C. to about 120° C. and At the nip, concurrently meltfusing the film to the nonwoven web material forming one or morediscrete bond sites between the film and the nonwoven web materiallocated proximate to a perimeter defined by at least one of theapertures and forming apertures in the film without substantiallysoftening a polymer of the nonwoven web material, wherein at least oneaperture has a length of from about 200 to about 5000 micrometers, andwherein the nonwoven web material remains generally unapertured afterbeing melt fused to the film and the nonwoven web material remainssubstantially unbonded to the film except at the discrete bond sites. 2.The method of claim 1, wherein the polymer composition comprises anelastomeric semi-crystalline polyolefin.
 3. The method of claim 2,wherein the semi-crystalline polyolefin is an ethylene/α-olefincopolymer, propylene/α-olefin copolymer, or a combination thereof. 4.The method of claim 2, wherein the semi-crystalline polyolefin issingle-site catalyzed.
 5. The method of claim 1, wherein the polymercomposition comprises an elastomeric block copolymer.
 6. The method ofclaim 1, wherein the stretch ratio is from about 3.0 to about 5.5. 7.The method of claim 1, wherein the elastic film is stretched prior topassing through the nip.
 8. The method of claim 1, wherein the elasticfilm is under tension in the machine direction.
 9. The method of claim1, wherein at least one of the apertures has a length of from about 350to about 4000 micrometers.
 10. The method of claim 1, wherein the rollis patterned with raised bonding elements.
 11. The method of claim 10,wherein at least one of the bonding elements is oriented from about 30°to about 150° relative to the machine direction.
 12. The method of claim10, wherein at least one of the bonding elements is oriented from about45° to about 135° relative to the machine direction.
 13. The method ofclaim 1, wherein the nip is formed between two rolls.
 14. The method ofclaim 13, wherein at least one of the rolls is heated to a surfacetemperature of from about 50° C. to about 160° C.
 15. The method ofclaim 13, wherein at least one of the rolls is heated to a surfacetemperature of from about 70° C. to about 120° C.
 16. The method ofclaim 13, wherein a pressure of from about 75 to about 600 pounds perlinear inch is applied at the nip.
 17. The method of claim 13, wherein apressure of from about 120 to about 200 pounds per linear inch isapplied at the nip.
 18. The method of claim 13, wherein the nonwoven webmaterial contains a polymer having a Vicat softening point of from about130° C. to about 200° C., and further wherein at least one of the rollsis heated to a temperature of from about 50° C. to about 120° C.
 19. Themethod of claim 1, wherein the nonwoven web material contains spunbondfibers, meltblown fibers, staple fibers, or a combination thereof. 20.The method of claim 1, wherein the polymer of the nonwoven web materialis a polyolefin.
 21. The method of claim 20, wherein the polyolefin ispolypropylene.
 22. The method of claim 1, wherein at least one discretebond site is formed between the film and the nonwoven web material thatis located proximate to a perimeter defined by at least one of theapertures.
 23. The method of claim 1, wherein the nonwoven web materialis substantially unapertured after being melt fused to the film.
 24. Themethod of claim 1, wherein an additional nonwoven web material is passedthrough the nip so that the elastic film is positioned between thenonwoven web materials.
 25. The method of claim 1, further comprisingallowing the composite to retract in the machine direction prior to orduring winding onto a roll.
 26. The method of claim 1, furthercomprising mechanically stretching the composite in at least thecross-machine direction.
 27. The method of claim 1, wherein at an areaadjacent to the aperture in the film, the nonwoven web material is freefrom apertures having a length of from about 200 to about 5000micrometers.
 28. The method of claim 1, wherein the nonwoven webmaterial is free from apertures having a length of from about 200 toabout 5000 micrometers after being melt fused to the film.
 29. Themethod of claim 1, wherein the composite is liquid permeable.
 30. Amethod of forming a nonwoven composite, the method comprising: Formingan elastic film from a polymer composition, the polymer compositioncontaining a single-site catalyzed polyolefin; Passing the film and anonwoven web material through a nip formed by two rolls, at least one ofwhich is patterned with raised bonding elements, wherein the film isunder tension at a stretch ratio of from about 2.5 to about 7.0 at thenip, and wherein the nonwoven web material contains a polyolefin havinga Vicat softening temperature of from about 130° C. to about 200° C. andfurther wherein at least one of the rolls is heated to a temperature offrom about 50° C. to about 120° C. and At the nip, concurrently meltfusing the film to the nonwoven web material forming one or morediscrete bond sites between the film and the nonwoven web materiallocated proximate to a perimeter defined by at least one of theapertures and forming apertures in the film without substantiallysoftening a polymer of the nonwoven web material, wherein at least oneaperture has a length of from about 200 to about 5000 micrometers, andwherein the nonwoven web material remains generally unapertured afterbeing melt fused to the film and the nonwoven web material remainssubstantially unbonded to the film except at the discrete bond sites.31. The method of claim 30, wherein the single-site catalyzed polyolefinincludes an ethylene/α-olefin copolymer, propylene/α-olefin copolymer,or a combination thereof.
 32. The method of claim 30, wherein thepolymer composition comprises an elastomeric block copolymer.
 33. Themethod of claim 30, wherein the stretch ratio is from about 3.0 to about5.5.
 34. The method of claim 30, wherein the elastic film is stretchedprior to passing through the nip.
 35. The method of claim 30, whereinthe elastic film is under tension in the machine direction.
 36. Themethod of claim 30, wherein the elastic film is under tension in thecross-machine direction.
 37. The method of claim 30, wherein at leastone of the apertures has a length of from about 350 to about 4000micrometers.
 38. The method of claim 30, wherein at least one of thebonding elements is oriented from about 45° to about 135° relative tothe machine direction.
 39. The method of claim 30, wherein a pressure offrom about 120 to about 200 pounds per linear inch is applied at thenip.
 40. The method of claim 30, wherein at least one discrete bond siteis formed between the film and the nonwoven web material that is locatedproximate to a perimeter defined by at least one of the apertures. 41.The method of claim 30, wherein the nonwoven web material issubstantially unapertured after being melt fused to the film.
 42. Themethod of claim 30, wherein an additional nonwoven web material ispassed through the nip so that the elastic film is positioned betweenthe nonwoven web materials.
 43. The method of claim 30, furthercomprising mechanically stretching the composite in at least thecross-machine direction.
 44. The method of claim 30, wherein at an areaadjacent to the aperture in the film, the nonwoven web material is freefrom apertures having a length of from about 200 to about 5000micrometers.
 45. The method of claim 30, wherein the nonwoven webmaterial is free from apertures having a length of from about 200 toabout 5000 micrometers after being melt fused to the film.
 46. Themethod of claim 30, wherein the composite is liquid permeable.